Gold Kilns. Portable Mini Gold Kilns by GPK. Display: List / Grid. Show: ... (1 to 3 ounces capacity for silver or copper) Made in the USA by GPK Company Melt 1 to 6 oz of gold or scrap metals (1 to 3 ounces capacity for.. $156.00 $149.95. Add to Wish List. Add to Compare.